Shear Capacity Model with Variable Orientation of Concrete Stress Field for RC Beams Strengthened by FRP/FRCM

Abstract

A design-oriented analytical model able to evaluate the shear capacity of RC beams strengthened with FRP/FRCM sheets or strips oriented in any direction is proposed. The formulation of the model is based on the variableinclination stress-field approach, aiming to extend the Eurocode 2 framework to beams strengthened in shear using FRP/FRCM. Complete, U-shaped and twoside wrapping schemes are considered. The influences of both steel and fiber composite transverse reinforcements on the orientation of the compressive concrete stress field in the web are taken into account. Interaction between steel and fiber transversal reinforcement is considered, adopting equations able to limit their global efficiencies. Effectiveness of the proposed model adopting different relations for the assessment of the effective composite and steel strains provided by international codes is investigated. Shear capacity values predicted by the model and those obtained using international codes are compared against experimental results proving the efficiency of the proposed model.